WO2018061140A1

WO2018061140A1 - Erroneous assembly prevention structure of internal combustion engine

Info

Publication number: WO2018061140A1
Application number: PCT/JP2016/078780
Authority: WO
Inventors: 田尻　和也
Original assignee: 本田技研工業株式会社
Priority date: 2016-09-29
Filing date: 2016-09-29
Publication date: 2018-04-05

Abstract

Provided is an erroneous assembly prevention structure of an internal combustion engine for preventing erroneous assembly of components of different models of an internal combustion engine. The erroneous assembly prevention structure of an internal combustion engine is configured such that, in a structure of an internal combustion engine in which parts that contact each other and that constitute the internal combustion engine are assembled by fitting together protrusions and recesses that are respectively provided to the parts, parts contacting each other in a first internal combustion engine 1, and parts contacting each other in a second internal combustion engine 101 of a different model from the first internal combustion engine 1 have different structures for fitting together the recesses and protrusions.

Description

Structure for preventing misassembly of internal combustion engines

The present invention relates to a structure for preventing erroneous assembly between components of an internal combustion engine.

In order to perform positioning when assembling between the parts that are in contact with each other of the internal combustion engine, a pin hole is provided in the mating surface of one component, and a knock pin is provided in a position facing the pin hole of the mating surface of the other component. There is an example (for example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 2000-220464

In Patent Document 1, in an internal combustion engine, a cylinder head is superimposed on a cylinder block protruding from a crankcase and fastened integrally. However, a pin hole is formed on a mating surface of the cylinder head, and the cylinder block is aligned. A knock pin protrudes from the surface facing the pin hole, and when the cylinder head is stacked and assembled on the cylinder block, the knock pin on the cylinder block side fits into the pin hole on the cylinder head side. The cylinder head can be accurately positioned with respect to the block.

The internal combustion engine is given a specific type in view of its structure and external shape.
The size of the knock pin used for positioning is substantially constant. In particular, the knock pin used for an internal combustion engine of a type with a close displacement is often the same, and therefore the cylinder head of an internal combustion engine of a different type with respect to one cylinder block. May be misconfigured.

The present invention has been made in view of the above points, and the object of the present invention is to provide a misconfiguration prevention structure for an internal combustion engine that prevents misconfiguration of components of different types of the internal combustion engine.

In order to achieve the above object, an erroneous assembly prevention structure for an internal combustion engine according to the present invention includes:
In the internal combustion engine misassembly prevention structure in which the components that are in contact with each other constituting the internal combustion engine are assembled by fitting the convex portion and the concave portion, respectively,
The parts of the first internal combustion engine that are in contact with each other and the parts of the second internal combustion engine that are different in type from the first internal combustion engine are different in the fitting structure of the convex part and the concave part.

According to this configuration, the parts of the first internal combustion engine that are in contact with each other and the parts of the second internal combustion engine that are different in type from the first internal combustion engine have different fitting structures between the convex portions and the concave portions. When trying to assemble a part of the second internal combustion engine of a different type to the part of the internal combustion engine of 1, the convex part and the concave part do not fit accurately and cannot be assembled. Understand and prevent misconfiguration.

In the above configuration,
The parts of the first internal combustion engine that are in contact with each other and the parts of the second internal combustion engine that are in contact with each other may have different sizes of the convex part and the concave part.

According to this configuration, the parts of the first internal combustion engine that are in contact with each other and the parts of the second internal combustion engine that are in contact with each other are different in the size of the protrusions and the recesses. If the parts of the second internal combustion engine of different types that are in contact with each other are to be assembled, the convex portion and the concave portion do not fit with high precision, and it is easily understood that the assembly is wrong, and erroneous assembly is prevented.

In the above configuration,
The parts of the first internal combustion engine that are in contact with each other and the parts of the second internal combustion engine that are in contact with each other may have different shapes of the convex part and the concave part.

According to this configuration, the parts that are in contact with each other of the first internal combustion engine and the parts that are in contact with each other of the second internal combustion engine have different shapes of the convex part and the concave part. When trying to assemble the parts of the second internal combustion engine of different types that come into contact with each other, the convex portion and the concave portion do not fit with high precision, and it is easy to recognize that it is an erroneous assembly, and an erroneous assembly is prevented.

The parts in contact with each other are a cylinder block and a cylinder head,
The convex portion and the concave portion may be provided on the mating surfaces of the cylinder block and the cylinder head, respectively.

According to this configuration, since the convex portion and the concave portion are respectively provided on the mating surfaces of the cylinder block and the cylinder head, the second internal combustion engine of a different type is provided in the cylinder block (or cylinder head) of the first internal combustion engine. When an engine cylinder head (or cylinder block) is to be assembled, the convex portion and the concave portion do not fit with high precision, and it is easily understood that the assembly is wrong, and the wrong assembly is prevented.

In the above configuration,
The convex portion provided on one mating surface of the cylinder block and the cylinder head is a rod-like member planted on the mating surface,
You may make it the said recessed part provided in the other mating surface of the said cylinder block and the said cylinder head be a pin hole formed in the same mating surface.

According to this configuration, since the convex portion protruding from one mating surface of the cylinder block and the cylinder head is a rod-like member implanted on the mating surface, the dedicated cylinder block in which the convex portion is integrally formed or Since it is not necessary to manufacture a cylinder head and an existing cylinder block and cylinder head can be processed and used, manufacturing cost can be reduced.

In the above configuration,
The convex portion provided on one mating surface of the cylinder block and the cylinder head is a projection formed integrally from the mating surface,
You may make it the said recessed part provided in the other mating surface of the said cylinder block and the said cylinder head be a hole part protruded and formed in the mating surface.

According to this configuration, the convex portion provided on one mating surface of the cylinder block and the cylinder head is a projection that is integrally formed by projecting from the mating surface. The attaching process is unnecessary and the number of manufacturing steps can be reduced.

In the above configuration,
The projection is provided on the mating surface of the cylinder block,
The concave portion may be provided on the mating surface of the cylinder head.

According to this configuration, when the cylinder head is assembled to the cylinder block, the convex portion is provided on the mating surface that is the upper surface of the cylinder block, which is normally the lower side. It can be easily fitted and assembled, and workability is good.
Moreover, there is a possibility that it can be recognized whether or not it is a wrong assembly before assembly by visual recognition of the convex portion.

In the above configuration,
The parts in contact with each other are a cylinder head and a camshaft,
The convex portion is an annular ridge that protrudes in the radial direction on the outer periphery of the journal portion of the camshaft and is formed in the circumferential direction,
The concave portion may be a groove formed in a circumferential direction on a bearing inner peripheral surface of the bearing portion of the cylinder head.

According to this configuration, the outer circumferential surface of the camshaft journal portion projects in the radial direction to form an annular ridge in the circumferential direction, and the inner circumferential surface of the bearing portion of the cylinder head has a groove in the circumferential direction. The camshaft protrusion is slidably fitted in the groove of the bearing portion of the cylinder head so that the camshaft is rotatably supported. The cylinder head (or camshaft) of the first internal combustion engine ) And the camshaft (or cylinder head) of the second internal combustion engine of a different model, the protrusions and grooves do not fit with high accuracy, and it is easy to find that the assembly is incorrect. Pairing is prevented.

In the above configuration,
The cylinder head and the camshaft of the first internal combustion engine and the cylinder head and the camshaft of the second internal combustion engine may have different axial widths of the protrusions and the grooves. Good.

According to this configuration, when the cam shaft (or cylinder head) of the second internal combustion engine of a different type is assembled to the cylinder head (or cam shaft) of the first internal combustion engine, Since the axial widths of each other do not match and the protrusions cannot be accurately fitted in the groove, it is easy to recognize that it is a wrong assembly, and the wrong assembly is prevented.

In the above configuration,
The parts in contact with each other are a camshaft and a camshaft holder,
The convex portion is an annular ridge that protrudes in the radial direction on the outer periphery of the journal portion of the camshaft and is formed in the circumferential direction,
The concave portion may be a groove formed in the circumferential direction on the inner peripheral surface of the bearing of the camshaft holder.

According to this configuration, the outer circumferential surface of the camshaft journal portion protrudes in the radial direction to form a circumferential annular ridge, and the camshaft holder has a circumferential groove on the inner circumferential surface of the bearing. And the camshaft is rotatably supported by a camshaft (or camshaft holder) of the first internal combustion engine, If you try to assemble the camshaft holder (or camshaft) of the second internal combustion engine with a different model, the ridges and grooves will not fit accurately, and it will be easy to see that they are misassembled. Is prevented.

In the above configuration,
The cam shaft (24) and the cam shaft holder (50R) of the first internal combustion engine (1), and the cam shaft (124) and the cam shaft holder (150R) of the second internal combustion engine (101). The axial widths of the protrusions (24r, 124r) and the grooves (50v, 150v) may be different from each other.

According to this configuration, when the camshaft holder (or camshaft) of the second internal combustion engine of a different type is assembled to the camshaft (or camshaft holder) of the first internal combustion engine, the protrusions and grooves Since the axial widths of the strips do not match and the protrusions cannot be fitted into the grooves with high accuracy, it can be easily recognized that the strips are misassembled, and misassembly is prevented.

According to the present invention, the fitting structure of the convex portion and the concave portion is different between the parts of the first internal combustion engine that are in contact with each other and the parts of the second internal combustion engine that are different in type from the first internal combustion engine. When trying to assemble a second internal combustion engine part of a different type to the internal combustion engine part of this type, the convex part and the concave part do not fit accurately and cannot be assembled. Misconfiguration is prevented.

1 is an overall left side view showing a partial cross section of a first internal combustion engine according to an embodiment of the present invention. It is the right view made into the principal part cross section which shows the assembly state of a cylinder block and a cylinder head. It is the decomposition | disassembly right view made into the principal part cross section which shows the decomposition | disassembly state of a cylinder block and a cylinder head. It is a top view of a cylinder block. FIG. 5 is a cross-sectional view taken along line VV in FIG. 4. It is a bottom view of a cylinder head. FIG. 7 is a cross-sectional view taken along arrow VII-VII in FIG. 6. It is principal part sectional drawing which shows the fitting state of a pin member and a pin hole. It is the decomposition | disassembly right view made into the principal part cross section which shows the decomposition | disassembly state of the cylinder block and cylinder head of a 2nd internal combustion engine. It is a top view of the cylinder head incorporating the valve operating mechanism of the internal combustion engine which concerns on another embodiment of this invention. It is a top view of a cylinder head. It is a bottom view of a right camshaft holder. It is XIII-XIII arrow sectional drawing of FIG. It is an exploded sectional view of the right side of a cylinder head, an intake camshaft, and a camshaft holder. FIG. 6 is an exploded cross-sectional view on the right side of a cylinder head, an intake camshaft, and a camshaft holder of a second internal combustion engine. It is sectional drawing which shows the state which assembled | attached the fuel injection valve to the throttle body of the 1st internal combustion engine. It is principal part sectional drawing which shows the decomposition | disassembly state of a throttle body and a fuel injection valve. It is a XVIII arrow directional view in FIG. 17 of a throttle body. It is a XIX arrow line view in FIG. 17 of a fuel injection valve. It is the figure seen from the same direction as FIG. 18 of the throttle body of a 2nd internal combustion engine. It is the figure seen from the same direction as FIG. 19 of the fuel injection valve of a 2nd internal combustion engine.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a side view of a first internal combustion engine 1 according to an embodiment to which the present invention is applied.
The first internal combustion engine 1 is mounted on a small vehicle such as a motorcycle.
In FIG. 1, the first internal combustion engine 1 is shown in a posture mounted on a vehicle (not shown).
In the description of the present specification, the front / rear and left / right directions follow the normal standard in which the straight direction of the vehicle is the front, and in the drawings, FR is the front, RR is the rear, LH is the left, RH Indicates the right side.

The first internal combustion engine 1 is a water-cooled, in-line 2-cylinder, 4-stroke cycle DOHC type internal combustion engine, and is given a specific type from its structure, outer shape, and the like.
The first internal combustion engine 1 is mounted horizontally on a vehicle so that a crankshaft 10 rotatably supported by a crankcase 2 is oriented in the left-right vehicle width direction.
The two cylinders of the cylinder block 3 are arranged side by side in series on the left and right.

As shown in FIG. 1, the crankcase 2 that supports the crankshaft 10 by arranging the crankshaft 10 in the vehicle width direction is configured in a vertically divided manner with the crankshaft 10 as a boundary.
A cylinder block 3 is integrally formed at the front upper part of the upper crankcase 2A by tilting the cylinder axis Lc of the two cylinder bores 3a somewhat forward, and the cylinder head 4 is overlapped and fastened to the cylinder block 3. The cylinder head cover 5 is put on the cylinder head 4 and fastened.
On the other hand, an oil pan 6 is attached under the lower crankcase 2B.

In the first internal combustion engine 1 of the present embodiment, a transmission 11 is incorporated in the crankcase 2 to constitute a so-called power unit.
The crankcase 2 extends rearward from the crankshaft 10, and in addition to the crankshaft 10, the main shaft 12, the countershaft 13, and the balancer of the transmission 11 disposed in the crankcase 2 rearward from the crankshaft 10. The shaft 14 is rotatably supported in parallel with the crankshaft 10.

As shown in FIG. 1, a piston 7 is fitted in a cylinder bore 3a (see FIG. 4) of two cylinders of a cylinder block 3 formed integrally with the upper crankcase 2A so as to be able to reciprocate. It is connected to the crankpin portion of the crankshaft 10 via the connecting rod 8.

The cylinder head 4 has a combustion chamber 20 formed opposite to the piston 7 for each of the two cylinder bores 3a, and an intake port 21 opened to the combustion chamber 20 and opened and closed by a pair of intake valves 22 to the rear. An exhaust port 31 opened and closed by a pair of exhaust valves 32 extends forward, and a spark plug 15 facing the combustion chamber 20 is mounted.
A throttle body 16 is connected to the upstream opening 21a of the intake port 21, and an air cleaner is connected upstream of the throttle body 16 via an intake pipe (not shown).
A muffler is connected to the downstream opening 31a of the exhaust port 31 via an exhaust pipe (not shown).

The intake valve 22 is urged in the valve closing direction by a valve spring 23 provided between the cylinder head 4 and the exhaust valve 32 is urged in the valve closing direction by a valve spring 33 provided between the intake valve 22 and the cylinder head 4. However, each intake valve 22 and each exhaust valve 32 are synchronized with the rotation of the crankshaft 10 by an intake camshaft 24 and an exhaust camshaft 34 that are rotatably supported by the cylinder head 4 in parallel with the crankshaft 10. Open and close.

For this purpose, the intake camshaft 24 and the exhaust camshaft 34 are fitted with an intake cam sprocket 29 and an exhaust cam sprocket 39 at the right end, respectively, and a chain drive sprocket 18 fitted near the right end of the crankshaft 10. The cam chain 19 is stretched between the intake cam sprocket 29 and the exhaust cam sprocket 39, and the intake camshaft 24 and the exhaust camshaft 34 are driven to rotate at half the rotational speed of the crankshaft 10.

Cam chain chambers

3c and 4c are formed at the right ends of the cylinder block 3 and the cylinder head 4 to communicate with each other (see FIGS. 4 and 6).

An intake rocker arm 25 that is swung by an intake cam 24c formed on the intake camshaft 24 is pivotally supported by the rocker arm shaft 26, and a roller 25r that is rotatably supported by the intake rocker arm 25 is provided with an intake cam 24c. When the rotation is pushed, the tip of the intake rocker arm 25 swings and pushes the intake valve 22 against the valve spring 23 to open the valve.
Similarly, an exhaust rocker arm 35 that is swung by an exhaust cam 34c formed on the exhaust camshaft 34 is pivotally supported by the rocker arm shaft 36, and a roller 35r that is rotatably supported by the exhaust rocker arm 35 is provided. When pushed by the rotation of the exhaust cam 34c, the tip of the exhaust rocker arm 35 swings and pushes the exhaust valve 32 against the valve spring 33 to open.

FIG. 2 is a right side view showing the assembled state of the cylinder block 3 and the cylinder head 4, and FIG. 3 is an exploded right side view showing an exploded state of the cylinder block 3 and the cylinder head 4.
In the right side view of the cylinder block 3 and the cylinder head 4 in FIGS. 2 and 3, the vicinity of the mating surface is a partial cross section.

As shown in FIG. 4, two cylinder bores 3a, 3a are formed side by side on the mating surface 3f of the cylinder block 3 with the cylinder head 4, and a long rectangular cam chain chamber 3c is front and rear on the right side thereof. Is formed.
Further, one stud bolt hole 3s is formed on the left, middle, and right sides of the two cylinder bores 3a, 3a, one on the front and one on the rear.

A circular hole 3h is formed in the boss portion 3b bulging rearward of the cam chain chamber 3c in the mating surface 3f of the cylinder block 3, and the first hole is formed in the circular hole 3h as shown in FIG. A pin member 3P, which is a cylindrical rod-like member having a predetermined outer diameter of the internal combustion engine 1, is implanted with its base portion being press-fitted.
The pin member 3P has a predetermined outer diameter a1 of the first internal combustion engine 1, and protrudes from the mating surface 3f of the cylinder block 3 (see FIG. 3).

A roller pin having a low pressure stress (narrow tolerance range) is used for the pin member 3P.
This roller pin 3P is basically detachable after being fitted into the circular hole 3h of the mating surface 3f of the cylinder block 3 and cannot be removed. Even if it can be removed, the inner diameter of the circular hole 3h expands or deforms. It becomes impossible to press-fit roller pins with the same dimensions.
Therefore, the roller pin 3P press-fitted into the cylinder block 3 of the first internal combustion engine cannot be replaced with a roller pin having a different size.

On the other hand, on the mating surface 4f of the cylinder head 4 with the cylinder block 3, as shown in FIG. 6, the combustion chamber recesses 4a of the

combustion chambers

20, 20 corresponding to the two cylinder bores 3a, 3a of the cylinder block 3, respectively. 4a is formed side by side, and a long rectangular cam chain chamber 4c is formed on the right and front sides thereof.

In the combustion chamber recess 4a, two intake ports 21 and two exhaust ports 31 are opened facing the combustion chamber 20, and a fitting insertion hole 4t for a spark plug 15 is formed in the center.
A stud bolt hole 4s corresponding to the stud bolt hole 3s of the cylinder block 3 is formed around the two combustion chamber recesses 4a and 4a.

A predetermined inner diameter of the first internal combustion engine 1 is provided on the mating surface 4f of the cylinder head 4 at a location facing the pin member 3P of the cylinder block 3 of the boss portion 4b bulging rearward of the cam chain chamber 4c. A pin hole 4H, which is a circular hole, is formed (see FIG. 7).
The inner diameter of the pin hole 4H of the cylinder head 4 is equal to the outer diameter a1 of the pin member 3P of the cylinder block 3, and has a predetermined inner diameter a1 of the first internal combustion engine 1 (see FIG. 3).
Therefore, the pin member 3P fits into the pin hole 4H with high accuracy (see FIG. 8).

Therefore, as shown in FIG. 3, when the mating surface 4 f of the cylinder head 4 is accurately opposed to the mating surface 3 f of the cylinder block 3 and the gasket 9 is sandwiched between them, they are shown in FIGS. 2 and 8. Thus, the pin member 3P on the cylinder block 3 side can be fitted into the pin hole 4H of the cylinder head 4 with high precision, and can be positioned and fixed with respect to each other. Thus, the cylinder head 4 is assembled to the cylinder block 3. In addition, the first internal combustion engine 1 can be manufactured.

FIG. 9 is an exploded right side view showing an exploded state of the cylinder block 103 and the cylinder head 104 of the second internal combustion engine 100 of a type different from that of the first internal combustion engine 1.
On the mating surface 103f of the cylinder block 103 formed integrally with the upper crankcase 102A of the second internal combustion engine 100, a circular hole is formed in the boss portion 103b bulging rearward of the cam chain chamber. A cylindrical pin member 103P having a predetermined outer diameter a2 of the second internal combustion engine 101 is planted with the base being press-fitted (see FIG. 9).
The pin member 103P protrudes from the mating surface 103f of the cylinder block 103.
A roller pin is also used for the pin member 103P.

On the other hand, on the mating surface 104f of the cylinder head 104 with the cylinder block 103, the second internal combustion engine 101 is located at a location facing the pin member 103P of the cylinder block 103 of the boss 104b bulging rearward of the cam chain chamber. A pin hole 4H, which is a circular hole having a predetermined inner diameter a2, is formed (see FIG. 9).
The outer diameter a2 of the pin member 103P on the cylinder block 103 side is equal to the inner diameter a2 of the pin hole 104H of the cylinder head 104, and the pin member 103P fits into the pin hole 104H with high accuracy.

Accordingly, as shown in FIG. 9, when the mating surface 104f of the cylinder head 103 is made to face the mating surface 103f of the cylinder block 103 accurately and the gasket 109 is sandwiched between them, a pin member on the cylinder block 103 side is obtained. 103P fits into the pin hole 104H of the cylinder head 104 with high precision and can be positioned and fixed with certainty. Thus, the cylinder head 104 is assembled to the cylinder block 103 to manufacture the second internal combustion engine 101. can do.

The diameter a2 of the pin member 103P and the pin hole 4H of the second internal combustion engine 101 is smaller than the diameter a1 of the pin member 3P and the pin hole 4H of the first internal combustion engine 1.
Accordingly, when the cylinder head 104 of the second internal combustion engine 101 of a different type is to be superimposed on the cylinder block 3 of the first internal combustion engine 1, the outer diameter a1 of the pin member 3P on the cylinder block 3 side is set to the cylinder head 104. The pin member 3P and the pin hole 104H cannot be fitted, and the cylinder head 104 cannot be assembled to the cylinder block 3 because it is larger than the inner diameter a2 of the side pin hole 104H.
For this reason, it is easy to recognize that it is a misconfiguration, and the misconfiguration can be prevented.

The pin member 3P press-fitted into the circular hole 3h of the mating surface 3f of the cylinder block 3 of the first internal combustion engine is a roller pin, and this roller pin is replaced with a roller pin of a second internal combustion engine having a different size. Since it is not possible, the cylinder head 104 of the second internal combustion engine 101 cannot be overlaid and assembled to the cylinder block 3 of the first internal combustion engine.

Further, when the cylinder head 4 of the first internal combustion engine is to be superimposed on the cylinder block 103 of the second internal combustion engine 101, the inner diameter a1 of the pin hole 4H on the cylinder head 4 side is the pin member 103P on the cylinder block 103 side. The pin member 103P and the pin hole 4H do not fit with high accuracy, and there is a gap, resulting in play, and the cylinder head 4 cannot be reliably positioned and fixed to the cylinder block 103.
Therefore, it can be easily understood that it is a misconfiguration, and the misconfiguration can be prevented.

Since the pin member 103P press-fitted into the cylinder block 103 of the second internal combustion engine 101 is also a roller pin and cannot be replaced with a roller pin having a different size, the cylinder block 103 of the second internal combustion engine 101 is replaced with the first internal combustion engine. The cylinder heads 4 cannot be assembled with each other.

Since the

pin members

3P and 103P are implanted on the

mating surfaces

3f and 103f of the

cylinder blocks

3 and 103, there is no need to manufacture a dedicated cylinder block in which convex portions corresponding to the pin members are formed. What is necessary is just to form the circular hole which can press-fit a pin member in a block, and can reduce manufacturing cost.

In the above embodiment, the pin member and the pin hole respectively provided on the mating surfaces of the cylinder block and the cylinder head have a circular cross section, but the cross section has a polygonal shape or other shapes, The pin member and pin hole of the internal combustion engine of 1 and the pin member and pin hole of the second internal combustion engine of different types may have different cross-sectional shapes.

For example, the cross-sectional shape of the pin member and the pin hole of the first internal combustion engine is a quadrangle, and the cross-sectional shape of the pin member and the pin hole of the second internal combustion engine is a pentagon. Star polygons such as star pentagons and star heptagons, ellipses with different shapes, oval shapes with different shapes, etc. can be employed.

In the above embodiment, the

pin members

3P and 103P of the

cylinder blocks

3 and 103 are implanted on the

mating surfaces

3f and 103f of the

cylinder blocks

3 and 103. However, they are integrally formed so as to protrude from the mating surfaces of the cylinder blocks. A protrusion may be formed, and a hole for fitting the protrusion may be formed on the mating surface of the cylinder head.
With such a configuration, the cylinder block is manufactured with the protrusions integrally formed, so that an assembling process for planting the pin member or the like by press-fitting or the like is unnecessary, and the number of manufacturing steps can be reduced.

Further, a concave portion may be provided on the mating surface of the cylinder block, and a convex portion may be provided on the mating surface of the cylinder head.
However, as shown in the above-described embodiment, a convex portion is provided on the mating surface of the cylinder block, and a concave portion is provided on the mating surface of the cylinder head, so that the convex surface on the upper surface of the cylinder block, which is normally lower, is projected. When installing the cylinder head to the cylinder block, the convex part on the upper surface of the cylinder block is easy to see, and the concave part of the cylinder head can be easily fitted and assembled while visually checking this convex part. And workability is good.
Moreover, there is a possibility that it can be recognized whether or not it is a wrong assembly before assembly by visual recognition of the convex portion.

Next, another embodiment will be described with reference to FIGS.
The internal combustion engine according to the present embodiment is applied to the first internal combustion engine 1 of the above-described embodiment, and the same reference numerals are used for parts.
FIG. 10 is a top view of the cylinder head 4, in which two rear intake valves 22 and two front exhaust valves 32 are provided on the ceiling walls of the left and

right combustion chambers

20, 20.
In the center of the ceiling wall of the combustion chamber 20, a fitting insertion hole 4t for the spark plug 15 is formed.

Referring to FIG. 11, a right bearing wall 4 </ b> R extending forward and backward along the right side of the ceiling wall of the right combustion chamber 20 is formed, and the left bearing divided into the left and right sides of the ceiling wall of the left combustion chamber 20.

Walls

4L, 4L are formed, and

central bearing walls

4C, 4C divided in the front-rear direction are formed between the ceiling wall of the right combustion chamber 20 and the ceiling wall of the left combustion chamber 20.

The right bearing wall 4R, the

central bearing walls

4C and 4C, and the

left bearing walls

4L and 4L are parallel to each other and are erected perpendicular to the axis of the crankshaft 10.
A cam chain chamber 4c is formed between the right outer wall of the cylinder head 4 and the right bearing wall 4R.

The upper surface of the right bearing wall 4R of the cylinder head 4 is a mating surface 4Rf (surface with a dotted pattern in FIG. 11) with the right camshaft holder 50R. The mating surface 4Rf includes the intake camshaft 24 and the exhaust cam. A semicircular bearing inner peripheral surface 4Ri for bearing the shaft 34 and a bearing inner peripheral surface 4Re are formed.

Further, the intake camshaft 24 and the exhaust camshaft 34 are also provided on the mating surfaces 4Lf and 4Lf (surfaces with a dotted pattern in FIG. 11) with the

left camshaft holders

50L and 50L on the upper surfaces of the

left bearing walls

4L and 4L. A semicircular bearing inner circumferential surface 4Li and a bearing inner circumferential surface 4Le are formed.
Similarly, the intake camshaft 24 and the exhaust camshaft are also provided on the mating surfaces 4Cf and 4Cf (surfaces with a dotted pattern in FIG. 11) with the

central camshaft holders

50C and 50C on the upper surfaces of the

central bearing walls

4C and 4C. A semicircular bearing inner peripheral surface 4Ci for bearing 34 and a bearing inner peripheral surface 4Ce are formed.

Then, the semicircular bearing inner peripheral surface 4Ri and the bearing inner peripheral surface 4Re of the right bearing wall 4R of the cylinder head 4 are formed with

semicircular arc grooves

4v and 4v in the circumferential direction (FIG. 11, FIG. 11). (See FIG. 14).

Grooves

4v and 4v formed on the bearing inner peripheral surfaces 4Ri and 4Re of the right bearing wall 4R have a predetermined axial width (groove width) b1 of the first internal combustion engine 1 (see FIG. 14).

On the other hand, the intake camshaft 24 includes journal portions 24Rj, which are respectively supported by the bearing inner peripheral surface 4Ri of the right bearing wall 4R, the bearing inner peripheral surface 4Ci of the central bearing wall 4C, and the bearing inner peripheral surface 4Li of the left bearing wall 4L. 24Cj and 24Lj, and

intake cams

24c and 24c are formed between the journal portions 24Rj and 24Cj and between the journal portions 24Cj and 24Lj (see FIGS. 10, 13, and 14).

An outer circumferential protrusion 24r is formed on the outer periphery of the right journal portion 24Rj of the intake camshaft 24 so as to project in the radial direction (see FIGS. 11 and 14).
A protrusion 24r formed on the right journal portion 24Rj of the intake camshaft 24 has a predetermined axial width (thickness) b1 of the first internal combustion engine 1 (see FIG. 14).
The axial width (groove width) b1 of the groove 4v formed on the bearing inner peripheral surface 4Ri of the right bearing wall 4R of the cylinder head 4 and the shaft of the protrusion 24r formed on the right journal portion 24Rj of the intake camshaft 24. The direction width (thickness) b1 is equal, and the protrusion 24r is slidably fitted into the groove 4v with high precision (see FIG. 13).

Therefore, as shown in FIG. 14, the bearing inner peripheral surfaces 4Ri, 4Ci of the right bearing wall 4R, the central bearing wall 4C, and the left bearing wall 4L of the cylinder head 4 in an attempt to incorporate the intake camshaft 24 into the cylinder head 4. 4Li, when the journal portions 24Rj, 24Cj, 24Lj of the intake camshaft 24 are fitted, as shown in FIG. 13, the protrusion of the journal portion 24Rj into the groove 4v of the bearing inner peripheral surface 4Ri of the right bearing wall 4R. The rib 24r can be rotated and accurately fitted to position the intake camshaft 24 reliably. The intake camshaft 24 is assembled to the right bearing wall 4R of the cylinder head 4 so that the first internal combustion engine 1 is Can be manufactured.

FIG. 15 is an exploded right side sectional view of the cylinder head 104 and the intake camshaft 124 of the second internal combustion engine 100 of a type different from that of the first internal combustion engine 1.
The semicircular bearing inner peripheral surface 104Ri of the right bearing wall 104R of the cylinder head 104 of the second internal combustion engine 100 is formed with a semicircular arc groove 104v in the circumferential direction.
A groove 104v formed on the bearing inner peripheral surface 104Ri of the right bearing wall 104R has a predetermined axial width (groove width) b2 of the second internal combustion engine 101 (see FIG. 15).

On the other hand, the intake camshaft 124 has a journal portion 124Rj that is supported by the bearing inner peripheral surface 104Ri of the right bearing wall 104R, and protrudes in the radial direction on the outer periphery of the journal portion 124Rj so as to protrude in the circumferential direction. 124r is formed.
A protrusion 124r formed on the right journal portion 124Rj of the intake camshaft 124 has a predetermined axial width (thickness) b2 of the second internal combustion engine 101 (see FIG. 15).
The axial width (groove width) b2 of the groove 104v formed on the bearing inner peripheral surface 104Ri of the right bearing wall 104R of the cylinder head 104 and the shaft of the protrusion 124r formed on the right journal portion 124Rj of the intake camshaft 124. The direction width (thickness) b2 is equal, and the protrusion 124r is slidably fitted into the groove 104v with high accuracy.

Accordingly, as shown in FIG. 15, the journal portion 124Rj of the intake camshaft 124 is fitted to the bearing inner peripheral surface 4Ri of the right bearing wall 4R of the cylinder head 104 in order to incorporate the intake camshaft 24 into the cylinder head 104. Then, the protrusion 124r of the journal portion 124Rj is rotatably and accurately fitted into the groove 104v of the bearing inner peripheral surface 104Ri of the right bearing wall 104R, so that the intake camshaft 124 can be positioned reliably, and the cylinder head 104 The second internal combustion engine 101 can be manufactured by assembling the intake camshaft 124 to the right bearing wall 104R.

The axial width b2 of the groove 104v and the protrusion 124r of the second internal combustion engine 101 is larger than the axial width b1 of the groove 4v and the protrusion 24r of the first internal combustion engine 1.
Accordingly, when the journal portion 124Rj of the intake camshaft 124 of the second internal combustion engine 101 of a different type is assembled to the bearing inner peripheral surface 4Ri of the right bearing wall 4R of the cylinder head 4 of the first internal combustion engine 1, The axial width (groove width) b1 of the groove 4v on the cylinder head 4 side is smaller than the axial width (thickness) b2 of the protrusion 124r on the intake camshaft 124 side, and the protrusion 124r fits into the groove 4v. The intake camshaft 124 cannot be assembled to the cylinder head 4.
For this reason, it is easy to recognize that it is a misconfiguration, and the misconfiguration can be prevented.

When the journal portion 24Rj of the intake camshaft 24 of the first internal combustion engine 1 is to be assembled to the bearing inner peripheral surface 104Ri of the right bearing wall 104R of the cylinder head 104 of the second internal combustion engine 101, the cylinder head 104 The axial width b2 of the groove 104v on the side is too larger than the axial width b1 of the protrusion 24r on the intake camshaft 24 side, and the groove 104v and the protrusion 24r do not fit with high accuracy, and there is a gap and there is a backlash. As a result, the intake camshaft 24 cannot be reliably positioned and fixed to the cylinder head 104.
Therefore, it can be easily understood that it is a misconfiguration, and the misconfiguration can be prevented.

The assembly of the cylinder head and the exhaust camshaft is the same as the assembly of the cylinder head and the intake camshaft, and the cylinder head and exhaust camshaft of the first internal combustion engine are different from each other in the second internal combustion engine. The cylinder head of the engine and the exhaust camshaft are different in the axial width of the groove and the protrusion, and do not fit with each other, thereby preventing erroneous assembly.

Next, still another embodiment will be described with reference to FIGS.
In the first internal combustion engine 1, the right journal portions 24Rj and 34Rj of the intake camshaft 24 and the exhaust camshaft 34 are supported by being sandwiched between the right bearing wall 4R of the cylinder head 4 and the right camshaft holder 50R.
As shown in FIGS. 12 and 14, semicircular arc-shaped

grooves

50v and 50v are formed in the circumferential direction on the bearing inner peripheral surfaces 50Ri and 50Re of the right camshaft holder 50R.

Grooves

50v and 50v formed on the bearing inner peripheral surfaces 50Ri and 50Re of the right camshaft holder 50R have a predetermined axial width (groove width) c1 of the first internal combustion engine 1 (see FIG. 14).
The axial width (thickness) c1 of the protrusion 24r formed in the right journal portion 24Rj of the intake camshaft 24 and the axial width of the groove 50v formed in the bearing inner peripheral surface 50Ri of the right camshaft holder 50R ( The groove width c1 is equal (see FIG. 14), and the protrusion 24r is slidably fitted into the groove 50v with high precision (see FIG. 13).

Therefore, as shown in FIG. 14, the right camshaft holder 50R is to be assembled into the intake camshaft 24, and the bearing inner peripheral surface 50Ri of the right camshaft holder 50R is inserted into the protrusion 24r of the journal portion 24Rj of the intake camshaft 24. When the groove 50v is fitted, the protrusion 24r of the intake camshaft 24 is fitted to the groove 50v of the right camshaft holder 50R with high precision so as to be rotatable, and the two can be reliably positioned with respect to each other.

FIG. 15 shows an exploded right side sectional view of the intake camshaft 124 and the right camshaft holder 150R of the second internal combustion engine 100 of a type different from that of the first internal combustion engine 1.
The protrusion 124r is formed in the journal portion 124Rj of the intake camshaft 124 of the second internal combustion engine 100.
The right camshaft holder 150R that pivotally supports the intake camshaft 124 of the second internal combustion engine 100 has a semicircular arc-shaped groove 150v formed in the circumferential direction on the bearing inner peripheral surface 150Ri.

The groove 150v formed in the bearing inner peripheral surface 150Ri of the right camshaft holder 150R has a predetermined axial width (groove width) c2 of the second internal combustion engine 101 (see FIG. 15).
The axial width (thickness) c2 of the protrusion 124r formed on the right journal portion 124Rj of the intake camshaft 124 and the axial width of the groove 150v formed on the bearing inner peripheral surface 150Ri of the right camshaft holder 150R ( (Groove width) c2 is equal (see FIG. 15), and the protrusion 124r is slidably fitted into the groove 150v with high accuracy.

Accordingly, as shown in FIG. 15, the right camshaft holder 150R is incorporated into the intake camshaft 124, and the bearing inner peripheral surface 150Ri of the right camshaft holder 150R is inserted into the protrusion 124r of the journal portion 124Rj of the intake camshaft 124. When the groove 150v is fitted, the protrusion 124r of the intake camshaft 124 is fitted to the groove 150v of the right camshaft holder 150R with high precision so that it can rotate freely, and the two can be positioned reliably.

The axial width c2 of the ridge 124r of the intake camshaft 124 of the second internal combustion engine 101 and the groove 150v of the right camshaft holder 150R is the ridge 24r of the intake camshaft 24 of the first internal combustion engine 1 and the right cam. It is larger than the axial width c1 of the groove 50v of the shaft holder 50R.
Therefore, when the right camshaft holder 50R of the first internal combustion engine 1 is assembled to the journal portion 124Rj of the intake camshaft 124 of the second internal combustion engine 101, the axial width of the protrusion 124r of the intake camshaft 124 is determined. (Thickness) c2 is larger than the axial width (groove width) c1 of the groove 50v of the right camshaft holder 50R, and the protrusion 124r cannot be fitted into the groove 50v. The shaft holder 50R cannot be assembled.
For this reason, it is easy to recognize that it is a misconfiguration, and the misconfiguration can be prevented.

Further, when the right camshaft holder 150R of the second internal combustion engine 101 is assembled to the journal portion 24Rj of the intake camshaft 24 of the first internal combustion engine 1, the axial width of the ridge 24r of the intake camshaft 24 is determined. (Groove width) c1 is smaller than the axial width (thickness) c2 of the groove 150v of the right camshaft holder 150R, the protrusion 24r and the groove 150v do not fit with high accuracy, and there is a gap, resulting in play, The right camshaft holder 150R cannot be reliably positioned on the intake camshaft 24.
Therefore, it can be easily understood that it is a misconfiguration, and the misconfiguration can be prevented.

In the above embodiments, the combination of the cylinder block and the cylinder head, the combination of the cylinder head and the camshaft, and the combination of the camshaft and the camshaft holder have been described. The misassembly prevention structure of the present invention can also be applied to combinations of other parts that come into contact.

For example, the misassembly prevention structure of the present invention can be applied to the assembly of the fuel injection valve to the intake pipe or the throttle body.
FIGS. 16 to 19 show an example in which the fuel injection valve 60 is assembled to the throttle body 16 in the first internal combustion engine 1.

FIG. 17 is a cross-sectional view showing an exploded state of the throttle body 16 and the fuel injection valve 60.
Referring to FIGS. 16 and 17, the throttle body 16 is connected to the opening end of the intake port 21 of the cylinder head 4 via a connecting pipe 65. The throttle body 16 is connected to the downstream side of the throttle valve 16v. Thus, a cylindrical holding portion 17 is formed that bulges outward and inserts and holds the fuel injection valve 60.
The cylindrical holding portion 17 penetrates so that the fitting insertion hole 17h joins obliquely from the outside with respect to the intake passage of the throttle body 16.

The outer opening end of the cylindrical holding portion 17 forms a diameter-expanded end portion 17e whose inner diameter and outer diameter are both increased.
A groove 17v is formed in a part of the inner peripheral surface of the enlarged diameter end portion 17e of the cylindrical holding portion 17 so as to be directed in the insertion direction of the fuel injection valve 60.
A groove 17v formed in the enlarged diameter end portion 17e of the cylindrical holding portion 17 has a predetermined width (groove width) d1 of the first internal combustion engine 1.

On the other hand, in the fuel injection valve 60, the outer diameter of the tip part 60a having the smallest diameter for injecting fuel is equal to the inner diameter of the fitting insertion hole 17h of the cylindrical holding part 17.
The flat cylindrical portion 60b continuous to the tip end portion 60a of the fuel injection valve 60 has an outer diameter larger than that of the tip end portion 60a and is equal to the inner diameter of the enlarged diameter end portion 17e of the cylindrical holding portion 17.

On the flat cylindrical portion 60b of the fuel injection valve 60, a protrusion 60r is formed at a position corresponding to the groove 17v of the enlarged diameter end portion 17e of the cylindrical holding portion 17 so as to be oriented in the insertion direction of the fuel injection valve 60. Has been.
The protrusion 60r of the fuel injection valve 60 has a predetermined width (thickness) d1 of the first internal combustion engine 1 in the same manner as the groove width of the groove 17v on the inner peripheral surface of the enlarged diameter end portion 17e of the cylindrical holding portion 17. Have.

Accordingly, as shown in FIG. 17, when the fuel injection valve 60 is fitted into the cylindrical holding portion 17 of the throttle body 16 with the respective center axes aligned, the tip end portion 60 a of the fuel injection valve 60 is fitted into the cylindrical holding portion 17. The flat cylindrical portion 60b of the fuel injection valve 60 is fitted inside the enlarged diameter end portion 17e of the cylindrical holding portion 17, and at this time, the protrusion 60r of the flat cylindrical portion 60b is fitted to the enlarged diameter end portion 17e. The fuel injection valve 60 is accurately fitted to the groove 17v on the inner peripheral surface of the cylinder and the fuel injection valve 60 is securely positioned, and the fuel injection valve 60 is assembled to the throttle body 16 as shown in FIG. The internal combustion engine 1 can be manufactured.

A throttle body 116 and a fuel injection valve 160 of a second internal combustion engine 100 of a different type from the first internal combustion engine 1 are shown in FIGS. 20 and 21, respectively.
As shown in FIG. 20, the throttle body 116 has substantially the same shape as the throttle body 16 of the first internal combustion engine 1, but is formed on the inner peripheral surface of the enlarged diameter end portion 117 e of the cylindrical holding portion 117. The groove 117v has a predetermined width (groove width) d2 of the second internal combustion engine 1 larger than a predetermined width (groove width) d1 of the groove 17v of the first internal combustion engine 1.
On the other hand, as shown in FIG. 21, the fuel injection valve 160 has substantially the same shape as the fuel injection valve 16 of the first internal combustion engine 1, but the ridge 160r formed in the flat cylindrical portion 160b has a cylindrical shape. The second internal combustion engine 100 has a predetermined width (thickness) d2 similar to the groove 117v on the inner peripheral surface of the enlarged diameter end portion 117e of the holding portion 117.

Therefore, when the fuel injection valve 160 is fitted and inserted into the cylindrical holding portion 117 of the throttle body 116 with the respective center axes aligned, the tip portion 160a of the fuel injection valve 160 is fitted into the insertion insertion hole 117h of the cylindrical holding portion 117, and The flat cylindrical portion 160b of the fuel injection valve 160 is fitted inside the enlarged diameter end portion 117e of the cylindrical holding portion 117. At that time, the protrusion 160r of the flat cylindrical portion 160b is a groove on the inner peripheral surface of the enlarged diameter end portion 117e. The second internal combustion engine 100 can be manufactured by fitting to 117v with high accuracy, positioning the fuel injection valve 160 reliably, and assembling the fuel injection valve 160 to the throttle body 116.

The width d2 of the groove 117v and the protrusion 160r of the second internal combustion engine 101 is larger than the width d1 of the groove 17v and the protrusion 60r of the first internal combustion engine 1.
Therefore, when the fuel injection valve 160 of the second internal combustion engine 101 of a different type is assembled to the throttle body 16 of the first internal combustion engine 1, the width of the groove 17v of the cylindrical holding portion 17 of the throttle body 16 ( The groove width d1 is smaller than the width (thickness) d2 of the protrusion 160r of the fuel injection valve 160, and the protrusion 160r cannot be fitted into the groove 17v, and the fuel injection valve 160 is assembled to the throttle body 16. I can't.
For this reason, it is easy to recognize that it is a misconfiguration, and the misconfiguration can be prevented.

Further, when the fuel injection valve 16 of the first internal combustion engine 1 is to be assembled to the throttle body 116 of the second internal combustion engine 101, the width (groove width) of the groove 117v of the cylindrical holding portion 117 on the throttle body 116 side. ) D2 is too larger than the width (thickness) d1 of the ridge 16r on the fuel injection valve 16 side, the groove 117v and the ridge 16r do not fit with high accuracy, and there is a gap, resulting in looseness. The fuel injection valve 16 cannot be reliably positioned and fixed.
Therefore, it can be easily understood that it is a misconfiguration, and the misconfiguration can be prevented.

The misconfiguration prevention structure for an internal combustion engine of the present invention has been described above. However, the aspect of the present invention is not limited to the above-described embodiment, and includes those implemented in various aspects within the scope of the gist of the present invention. It is a waste.

DESCRIPTION OF SYMBOLS 1 ... 1st internal combustion engine, 2 ... Crankcase, 2A ... Upper crankcase, 2B ... Lower crankcase,
3 ... cylinder block, 3a ... cylinder bore, 3b ... boss part, 3c ... cam chain chamber, 3f ... mating surface, 3s ... stud bolt hole, 3P ... pin member (roller pin),
4 ... Cylinder head, 4f ... Mating surface, 4a ... Combustion chamber recess, 4b ... Boss part, 4c ... Cam chain chamber, 4s ... Stud bolt hole, 4H ... Pin hole, 4t ... Insertion hole,
4R ... right bearing wall, 4Rf ... mating surface, 4Ri, 4Re ... bearing inner peripheral surface, 4v ... groove, 4L ... left bearing wall, 4Li, 4Le ... bearing inner peripheral surface, 4C ... central bearing wall, 4Ci, 4Ce ... Bearing inner peripheral surface,
5 ... Cylinder head cover, 6 ... Oil pan, 7 ... Piston, 8 ... Connecting rod, 9 ... Gasket,
10 ... Crankshaft, 11 ... Transmission, 12 ... Main shaft, 13 ... Counter shaft, 14 ... Balancer shaft, 15 ... Spark plug,
16 ... Throttle body, 17 ... Cylinder holder, 17v ... Groove,
18 ... Chain drive sprocket, 19 ... Cam chain, 20 ... Combustion chamber, 21 ... Intake port, 22 ... Intake valve, 23 ... Valve spring,
24 ... intake camshaft, 24c ... intake cam, 24Rj, 24Cj, 24Lj ... journal part, 24r ... ridge,
25 ... Intake rocker arm, 26 ... Rocker arm shaft, 29 ... Intake cam sprocket,
31 ... Exhaust port, 32 ... Exhaust valve, 33 ... Valve spring, 34 ... Exhaust camshaft, 34c ... Exhaust cam, 39 ... Exhaust cam sprocket,
50R ... right camshaft holder, 50Ri, 50Re ... bearing inner peripheral surface, 50v ... groove, 50L ... left camshaft holder, 50C ... center camshaft holder,
60 ... Fuel injection valve, 60r ... Projection,
101 ... Second internal combustion engine, 102A ... Upper crankcase, 103 ... Cylinder block, 103b ... Boss portion, 103f ... Mating surface, 103P ... Pin member (roller pin),
104 ... Cylinder head, 104f ... Mating surface, 104b ... Boss, 104H ... Pin hole,
104R ... right bearing wall, 104Ri ... bearing inner peripheral surface, 104v ... groove,
116 ... Throttle body, 117 ... Cylinder holder, 117v ... Groove,
124 ... intake camshaft, 124c ... intake cam, 124Rj ... journal part, 124r ... ridge,
150R ... Right camshaft holder, 150Ri ... Bearing inner surface, 150V ... Groove,
160 ... Fuel injection valve, 160r ... Projection.

Claims

In the internal combustion engine misassembly prevention structure in which the components that are in contact with each other constituting the internal combustion engine are assembled by fitting the convex portion and the concave portion, respectively,
The parts that are in contact with each other of the first internal combustion engine (1) and the parts that are in contact with each other of the second internal combustion engine (101) of a different type from the first internal combustion engine (1) are the fitting of the convex part and the concave part. A structure for preventing erroneous assembly of an internal combustion engine, characterized in that the structure is different.
The size of the convex portion and the concave portion of the first internal combustion engine (1) and the second internal combustion engine (101) are different from each other. The structure for preventing misconfiguration of the internal combustion engine as described.
The projecting part and the recessed part are different in shape between the part of the first internal combustion engine (1) that contacts each other and the part of the second internal combustion engine (101) that contact each other. Structure for preventing misassembly of internal combustion engines.
The parts in contact with each other are a cylinder block (3, 103) and a cylinder head (4, 104),
The convex portions (3P, 103P) and the concave portions (4H, 104H) are provided on the mating surfaces (3f, 4f, 103f, 104f) of the cylinder block (3, 103) and the cylinder head (4, 104), respectively. The structure for preventing misassembly of an internal combustion engine according to any one of claims 1 to 3.
The convex portions (3P, 103P) provided on one mating surface (3f, 103f) of the cylinder block (3, 103) and the cylinder head (4, 104) are planted on the mating surface (3f, 103f). It is a rod-shaped member (3P, 103P),
The recesses (4H, 104H) provided on the cylinder block (3, 103) and the other mating surface (4f, 104f) of the cylinder head (4, 104) are formed to protrude into the mating surface (4f, 104f). 5. The structure for preventing erroneous assembly of an internal combustion engine according to claim 4, wherein the pin hole is formed into a pin hole (4H, 104H).
The convex portions (3P, 103P) provided on one mating surface (3f, 103f) of the cylinder block (3, 103) and the cylinder head (4, 104) project from the mating surface (3f, 103f) and are integrated. Formed protrusions,
The recesses (4H, 104H) provided on the other mating surfaces (4f, 104f) of the cylinder block (3, 103) and the cylinder head (4, 104) are formed to protrude into the mating surfaces (4f, 104f). 5. The structure for preventing erroneous assembly of an internal combustion engine according to claim 4, wherein the structure is a hole.
On the mating surface (3f, 103f) of the cylinder block (3, 103), the convex portion (3P, 103P) is provided,
5. The structure for preventing misassembly of an internal combustion engine according to claim 4, wherein the recesses (4H, 104H) are provided on the mating surfaces (4f, 104f) of the cylinder head (4, 104).
The parts in contact with each other are a cylinder head (4, 104) and a camshaft (24, 124),
The convex portion is an annular ridge (24r, 124r) formed in the circumferential direction so as to protrude radially on the outer periphery of the journal portion (24Rj, 124Rj) of the camshaft (24, 124),
The concave portion is a groove (4v, 104v) formed in a circumferential direction on a bearing inner peripheral surface (4Ri, 104Ri) of a bearing portion (4R, 104R) of the cylinder head (4, 104). The structure for preventing misassembly of an internal combustion engine according to any one of claims 1 to 4.
The cylinder head (4) and the camshaft (24) of the first internal combustion engine (1) and the cylinder head (104) and the camshaft (124) of the second internal combustion engine (101) 9. The misassembly prevention structure for an internal combustion engine according to claim 8, wherein the protrusions (24r, 124r) and the grooves (4v, 104v) have different axial widths.
The parts in contact with each other are a camshaft (24,124) and a camshaft holder (50R, 150R),
The convex portion is an annular ridge (24r, 124r) formed in the circumferential direction so as to protrude radially on the outer periphery of the journal portion (24Rj, 124Rj) of the camshaft (24, 124),
The concave portion is a groove (50v, 150v) formed in a circumferential direction on a bearing inner peripheral surface (50Ri, 150Ri) of the camshaft holder (50R, 150R). 4. The misassembly prevention structure for an internal combustion engine according to any one of items 3 to 4.
The cam shaft (24) and the cam shaft holder (50R) of the first internal combustion engine (1), and the cam shaft (124) and the cam shaft holder (150R) of the second internal combustion engine (101). 11. The structure for preventing erroneous assembly of an internal combustion engine according to claim 10, wherein the protrusions (24 r, 124 r) and the grooves (50 v, 150 v) have different axial widths.